This invention relates to thermometers for monitoring the temperature gradients of aquariums. As will be appreciated, fish are sensitive to temperature variations. This is particularly true of tropical fish, many varieties of which are extemely sensitive to sudden changes in their environment. These fish may succumb to a change in temperature in the aquarium body of water when they are exposed to such temperature changes, even for short periods of time. Because of these problems, many forms of aquarium tank pumps and recirculating systems have been devised in order to constantly circulate the water of the tank through aerators and heaters in order to maintain an equilibrium temperature and oxygen content of the body of water contained in the aquarium.
However, at times, because of inadequate positioning of the outlets for the recirculation system and because of minor movements or changes in the positioning of those outlets, the circulation can be such as to allow for portions of the body of water in the aquarium tank to vary in temperature by several degrees from the upper level of the body of water to the depths thereof. Obviously, such variations may be determined by positioning several different thermometers in a tank. Indeed, Aquarium thermometers have been constructed to hang over the side wall of the tank, to float in the tank, or to sink to the bottom of the tank to provide for a single depth position of the thermometer. These thermometers measure only the temperature where the sensing bulb of the thermometer is positioned. With a conventional aquarium tank with a body of water having a depth of, for example, two feet, the sensing bulb of the thermometer may be positioned approximately one foot below the surface of the body of water. Thus, the thermometer is measuring only the prevailing temperature in the body of water in the aquarium tank at a level halfway from the bottom to the top. Because of the fluctuations in circulation noted above, the prevailing temperature at the bottom of the tank may vary by several degrees from the prevailing temperature at the top or surface of the body of water. Thus, fish swimming in the tank may be exposed to a substantial variation in temperature between the top and the bottom of the tank.
Of course, temperature gradients may be measured simply by moving one conventional thermometer from the top of the tank toward the bottom, in order to measure the temperature there. However, this requires inserting a hand or an instrument into the tank, which may contaminate the tank and disturb the fish unnecessarily.
Moreover, this may require holding the thermometer at a position for several minutes to secure an intermediate level reading.
With the thermometer assembly of the present invention by contrast, a new and improved aquarium thermometer instrument is provided which allows for positioning the thermometer horizontally at any level along a vertical wall of the aquarium tank, with that positioning being determined and controlled from outside the tank, with no need for insertion of any objects or hands in the tank water for moving the thermometer from one level to another. This is achieved by mounting the thermometer in a waterfront housing containing a spaced pair of ferrous or magnetic components. A separate positioning handle is placed opposite the thermometer housing on the outside of the wall in registry with the housing. The handle, in turn, contains a spaced pair of ferrous or magnetic components. Thus, the ferrous or magnetic component of the handle attract the ferrous or magnetic components contained in the thermometer housing so that by moving the handle on the outside of the wall of the tank the thermometer housing inside the aquarium is moved to various levels, as desired, for determining the prevailing temperature at different depths in the tank.
With the foregoing and additional objects in view, this invention will now be described in more detail, and other objects and advantages thereof will be apparent from the following description, the accompanying drawings, and the appended claims.